Abstract: Based on the laboratory interface shear test results, a method of estimating the pullout load-displacement is proposed considering the embedded depth and the relative displacement relationship of the grout-soil interface. Firstly, the normal stress for the interface shear test can been obtained according to the embedded depth of the soil anchor. Then the fitting formulas were obtained by the laboratory interface shear tests and the curve fitting method. Secondly, based on the elastic deformation assumption of the anchoring segment and the Mindlin solution of the soil deformation, the relative displacement formula is proposed for the anchoring segment and the soil of interface. Finally, according to fitting curves of the shear test and the interface relative deformation, a formula for the pullout load with the displacement is established. The results indicate that curves of the anchor pullout load-displacement are more consistent with curves by the laboratory shear test than the other theoretical methods. The axial force and the relative displacement of the anchoring segment interface raised from the top to the end with the improvement of the pullout load of the soil anchor. The relative displacement curves show an obvious concave-characteristics, while the axial force curves of the anchoring segment show the strong convex-characteristics. In addition, with the increase of the pullout load, the friction resistance increases gradually, and range of friction resistance is gradually expanded. The greater the embedded depth, the smaller the resistance. The friction resistance of the anchoring segment has an obvious hysteresis phenomenon for the embedded depth of the soil anchor.

Key words: Soil Anchor, Pullout Mechanical, Friction Resistance, Relative Displacement, Mindlin Solution